The punctuation of the word "however" depends on its role in the sentence:

• When "however" is used as a conjunctive adverb to connect two independent clauses, it should be preceded by a semicolon and followed by a comma. For example: "I went to the store; however, it was closed."
• When "however" is used in the middle of a clause to mean "nevertheless" or to add contrast, it is set off by commas on both sides: "The weather was cold. The city, however, was lively."
• When "however" begins a sentence to introduce a contrasting statement, it is followed by a comma: "However, the results were unexpected."
• When "however" means "no matter how" or "in whatever way," it does not take commas: "However you do it, just finish the task."
• When "however" appears at the end of a clause or sentence, it should be preceded by a comma: "The doorbell rang; there was nobody there, however."
• Important to note: "however" is not a coordinating conjunction like "but," so using just a comma before it to join two independent clauses (comma splice) is incorrect.

These punctuation rules help clarify whether "however" is linking two complete ideas or modifying part of the sentence, and ensure the sentence is grammatically correct and clear.